6821 Other Deuterium-Labeled Compounds. Hexanol-4,4-d~,hexanol3,342, hexanol-2,2-d2,hexanol-1 ,I& and heptanol-l,l-dzwere prepared in a similar fashion and on a similar scale as the previously described deuterium-labeled compounds. Deuterium labeling was accomplished in each instance by reducing the appropriate carboxylic acid with lithium aluminum deuteride. 28 Heptanal:3,3-dz was prepared from pentyl-l,l-dzbromide by the method of Meyers,
Preparation of the o-N-Methylaminobenzoate Esters of the Deuterium-Labeled Compounds.24 In the case of hexanol-3,3-dz, N-methylisatoic anhydride (71 mg) was added to a mixture of 2 ml of dry dioxane, one-half pellet of potassium hydroxide (crushed), and hexanol-3,3-dz (42 mg). The mixture was heated (70") for 10 min. After drying over magnesium sulfate and concentration, the product ester was purified by preparative tlc (ether-hexane 1 : 1).
et al. 2o
Mass spectrometry indicated the presence of 97% dz and 3z dl species. Similar procedure was followed for the other labeled
alcohols.
(26) Purchased from Karl Roth OHG, Karlsruhe, Germany.
Haller-Bauer Cleavage of Cyclopropyl Phenyl Ketones Carl L. Bumgardner and Kenneth G . McDaniel Contribution from the Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27607. Received July 10, 1969 Abstract: A number of cyclopropyl phenyl ketones substituted on the small ring were subjected to the HallerBauer reaction to resolve some inconsistencies in the literature and to learn more of the factors which determine the direction of cleavage. The results may be understood in terms of fragmentation to give the more stable carbanion intermediate except in the cases of (Z)-2-phenylcyclopropyl phenyl ketone and 1-methyl-2,2-diphenylcyclopropyl phenyl ketone. Steric relief appears to play an important role in these two examples. The original report of Haller and Benoist regarding the major products from cleavage of 1-methylcyclopropylphenyl ketone is believed to be in error.
T
he cleavage of nonenolizable ketones with sodium amide, the Haller-Bauer reaction, has been known for some time and has been reviewed by Hamlin and Weston. The reaction is believed t o proceed by attack of amide ion on the carbonyl carbon giving rise t o an intermediate which decomposes t o yield ultimately a hydrocarbon and a carboxamide.2 Scheme I 0
/I
R-C-R'
+ NaNHi -+ 0
ka
1-ROI
R-C-RI-I
I
0
I/ + C-R' +RH + C-R' I/ I
-NH
-NH
I
NHz
NHz
As shown in Scheme I, if the groups originally attached t o the keto carbonyl are different then cleavage may occur in two directions. Any preference for the mode of cleavage would be expected t o be a reflection of the relative stability of the carbanions involved.2g3 Some apparent anomalies become obvious, however, when the results of substituted cyclopropyl phenyl ketone cleavages are examined. Haller and Beniost4 re(1) K. E. Hamlin and A . W. Weston, Org. Reactions, 9,1 (1957). (2) (a) J. F. Bunnett and B. F. Hrutfiord, J . Org. Chem., 27, 4152 (1962); (b) G. W. Kenner, M. J. T. Robinson, C. M. B. Taylor, and B. R. Webster. J . Chem. Soc.. 1756 (1962). (3) A. Streiiwieser, Jr., and R. G . Lkver, J . Amer. Chem. SOC.,87, 5388 (1965). (4)'A. Haller and E. Benoist, Ann. Chim. (Paris), [9]17,25 (1923).
ported that 1-methylcyclopropyl phenyl ketone underwent cleavage t o give benzamide and a gas, presumably methylcyclopropane, both in unspecified yield. In the course of a study of the stereochemistry of cyclopropyl carbanions, Impastato and Walborskyj subjected 1methyl-2,2-diphenylcyclopropyl phenyl ketone t o sodium amide and isolated in high yield l-methyl-2,2-diphenylcyclopropane. In contrast t o these observations where benzamide and a cyclopropyl hydrocarbon were the major products, Piehl and Brown6 noted that cleavage of 1-benzylcyclopropyl phenyl ketone led t o 1benzylcyclopropanecarboxamide in at least 56 yield. Their finding was later confirmed in this laboratory when the Haller-Bauer reaction was used as a step in the synthesis of phenyl~piropentane.~ Hamlin and Biermacher* reported that l-alkylcyclohexyl, 1-alkylcyclopentyl, and 1-alkylcyclobutyl phenyl ketones all gave mainly the corresponding l-alkylcycloalkanecarboxamides. To resolve some of these inconsistencies and t o obtain information concerning factors which might influence the stability of cyclopropyl anions, we studied the Haller-Bauer cleavage of several substituted cyclopropyl phenyl ketones. The earlier work of Haller and Benoist4 was also repeated so that their results could be placed on a quantitative basis.
Preparation of Ketones 1-Methylcyclopropyl phenyl ketone was prepared in 81 yield by treatment of cyclopropyl phenyl ketone with triphenylmethylpotassium followed by methyl ( 5 ) F. J. Impastato and H. M. Walborsky, J . Amer. Chem. Soc., 84, 4838 (1962). (6) F. J. Piehl and W. G.Brown, ibid., 75,5023 (1953). (7) C.L.Bumgardner, J . Org. Chem., 29,767 (1964). (8) I
